We both agreed that my ball hit the peak of its stretch on the drop a little too early, and he also pointed out that my ball remained in the squashed position once it began the jump, which looked a bit weird — it needed to stretch as soon as it left the ground. There was a similar issue with the landing — the ball squashed before it even hit the ground.
The faster speed seems better to me, but I think the stretch is still too early! It also seems to me like the ball comes down a little too quickly — I may try increasing the ball's delay at the peak of its jump, or just slow down the beginning of the drop a little.
I also went back and tried to correct the same squashing/stretching issues in my other bounce, the one with multiple jumps:
Something still seems at odds to me about this one, but I'm not quite sure what it is exactly. I think that maybe the ball hangs in the air a little too long on the first (and smallest) bounce, or maybe that it doesn't hold its initial downwards/preparatory squash long enough. The ball's squashes on each impact with the ground are also quite quick/sudden, so maybe I need to look at holding the squashes on-screen for just a little bit longer?